Various injector assist devices for facilitating hypodermic injections for in-home use, such as for insulin injections, are known for operation with conventional hypodermic syringes while simultaneously controlling the depth of penetration of the hypodermic needle. However, for an individual with impaired vision or manual dexterity, these injector assist devices have a number of disadvantages that make them inconvenient and less desirable to use. One disadvantage associated with some present injector assist devices is that, by virtue of the number of components from which the devices are comprised, they are complicated with respect to assembly of the device. For example, in the case of U.S. Pat. No. 5,634,906 of Haber et al., several components of the apparatus are adapted with various peripheral retaining grooves and ridges so that they may interface precisely in combination with each component of a dose metering syringe, i.e. the medication housing, medication cartridge, needle hub and barrel. As such, considerable coordination is required to ensure that each component of the device is properly interfaced in combination with each component of the syringe so that it may function properly. Another disadvantage found among other injector assist devices is that they have components sized to accommodate only a limited number of commercial syringes and therefore, are not compatible with a medication pen. Examples of these devices are disclosed in U.S. Pat. No. 4,601,708 of Jordan and Canadian Patent No. 536,718 of Transue. On the other hand, some prior art injector devices are more simplistic in design, comprising essentially one tubular component adapted to fit over the barrel of a syringe. Such devices, described, for instance, in U.S. Pat. No. 5,417,662 of Hjertman et al. and U.S. Pat. No. 4,373,526 of Kling, have a number of angled surfaces within the interior wall of a tube, which are designed to inter-fit and inter-engage with annular projections of a conventional syringe barrel. However, the interlocking arrangement between the injector assist device and the syringe makes the device more difficult to manipulate in terms of its attachment to and/or removal from a syringe, especially for a person with poor manual dexterity.